mtd: docg3: dereferencing an ERR_PTR() in docg3_probe()

If doc_probe_device() returned an ERR_PTR, then we accidentally saved
that to docg3_floors[floor] = mtd; which gets derefenced in the error
handling when we call doc_release_device().

I've reworked the error handling to take care of that and hopefully
make it a little simpler.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 12 insertions, 9 deletions

diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index d7df3114aa17..f7490a014e78 100644
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -2027,21 +2027,24 @@ static int __init docg3_probe(struct platform_device *pdev)
         if (!docg3_bch)
                 goto nomem2;
 
-        ret = 0;
         for (floor = 0; floor < DOC_MAX_NBFLOORS; floor++) {
                 mtd = doc_probe_device(base, floor, dev);
-                if (floor == 0 && !mtd)
-                        goto notfound;
-                if (!IS_ERR_OR_NULL(mtd))
-                        ret = mtd_device_parse_register(mtd, part_probes,
-                                                        NULL, NULL, 0);
-                else
+                if (IS_ERR(mtd)) {
                         ret = PTR_ERR(mtd);
+                        goto err_probe;
+                }
+                if (!mtd) {
+                        if (floor == 0)
+                                goto notfound;
+                        else
+                                continue;
+                }
                 docg3_floors[floor] = mtd;
+                ret = mtd_device_parse_register(mtd, part_probes, NULL, NULL,
+                                                0);
                 if (ret)
                         goto err_probe;
-                if (mtd)
-                        found++;
+                found++;
         }
 
         ret = doc_register_sysfs(pdev, docg3_floors);